Wet pad strike off system

ABSTRACT

A wet pad strike off system includes a frame adapted to rest on a base structure on which a quantity of wet concrete is placed. A blade is suspended from the frame for relative rotation in a plane. Coupled to the blade is the means for sensing elevation of the blade relative to a grade plane. Coupled to the frame is the means for facilitating adjustment of the frame relative to the base structure so that the blade&#39;s rotational plane can be positioned parallel to the grade plane. Coupled to at least one of the blade and frame is means for positioning the blade&#39;s rotational plane coincident with the grade plane.

FIELD OF THE INVENTION

The invention relates generally to concrete strike off devices and systems, and more particularly to concrete strike off system that can be used to create a small pad of wet concrete at a desired grade.

BACKGROUND OF THE INVENTION

The goal of a concrete strike off operation is to provide a smooth concrete surface at a desired grade plane. To do this over a large area, one or more “wet pads” of concrete (e.g., typically a couple of square feet in area) at the desired grade plane are manually struck off with the resulting wet pads forming reference or starting points for the larger concrete strike off operation. Currently, the creation of a wet pad is performed by a variety of manual means which can vary from wet pad to wet pad on a given job site. This is a time consuming process. Furthermore, the inconsistencies inherent in manual wet pad formation lead to inconsistent concrete finishing operations since the wet pad reference points may not all reside on the desired grade plane.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a system for performing a wet pad strike off.

Another object of the present invention is to provide a wet pad strike off system that consistently forms wet pads at a desired grade level.

Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.

In accordance with the present invention, a wet pad strike off system is provided. A frame has at least one support adapted to rest on a base structure on which a quantity of wet concrete is placed. A blade is coupled to and is suspended from the frame for relative rotation in a plane. Coupled to the blade is the means for sensing elevation of the blade relative to a grade plane. Coupled to the frame is the means for facilitating adjustment of the frame relative to the base structure so that the blade's rotational plane can be positioned parallel to the grade plane. Coupled to at least one of the blade and frame is means for positioning the blade's rotational plane coincident with the grade plane.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments and to the drawings, wherein corresponding reference characters indicate corresponding parts throughout the several views of the drawings and wherein:

FIG. 1 is a top-level schematic view of a wet pad strike off system in accordance with the present invention;

FIG. 2 is a schematic view of one embodiment of a wet pad strike off system;

FIG. 3 is a schematic view of another embodiment of a wet pad strike off system;

FIG. 4 is a side view of an exemplary construction of the wet pad strike off system embodiment schematically shown in FIG. 2;

FIG. 5 is a head on view taken along line 5-5 in FIG. 4;

FIG. 6 is a side view of an exemplary construction of the wet pad strike off system embodiment schematically shown in FIG. 3;

FIG. 7 is a head on view taken along line 7-7 in FIG. 6;

FIG. 8 is a plan view of an S-shaped blade; and

FIG. 9 is a cross-sectional view of the blade taken along line 9-9 in FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings and more particularly to FIG. 1, a wet pad strike off system in accordance with the present invention is shown schematically and is referenced generally by numeral 10. Wet pad strike off system 10 is a portable system that can be readily moved/operated by one person to generate a wet pad at a desired grade level at any desired location on a job site. At any given location, there will be a base structure 100 on which a quantity of unfinished and wet concrete 102 is deposited. Concrete 102 has a surface 104 that is higher than a desired finish grade level A-A or has areas above and below grade level A-A as shown. As would be understood by one of ordinary skill in the art, the goal of a wet pad strike off operation is to make surface 104 coincide with grade level A-A over a relatively small area on the order of a couple of square feet. The resulting wet pad serves as a reference point for the larger concrete strike off operation.

At its most basic level, wet pad strike off system 10 has a frame 12 that includes a support 14 that rests on base 100 when system 10 is positioned for a wet pad strike off operation. Supported in a suspended fashion from frame 12 is a blade 16, the lower edge of which is designated by 16A. Further, blade 16 is mounted such that it can rotate as indicated by arrow 18 thereby rotating lower edge 16A in a plane B-B. Blade 16 is coupled to frame 12 such that angular movement of frame 12 results in corresponding angular movement of plane B-B. Blade 16 is also mounted such that it can be moved in a direction perpendicular to plane B-B as indicated by two-headed arrow 20.

Frame 12 has one or more level sensor(s) 22 mounted thereon that provide indications of the orientation of frame 12 relative to a local datum. Since it is generally desirable for the concrete's grade level A-A to be parallel to or coincident with a local datum, the leveling of frame 12 (using sensor(s) 22) will position plane B-B of blade 16 parallel to grade level A-A.

Coupled to blade 16 is an elevation sensor 24 that can sense the position of blade 16 relative to a local horizontal datum. More specifically, elevation sensor 24 is coupled to blade 16 to sense the position of plane B-B relative to grade level A-A. If plane B-B and grade level A-A are parallel to one another, elevation sensor 24 can be used to position plane B-B coincident with grade level A-A as will be explained further below.

In operation, system 10 is transported to a location and support 14 is rested on base structure 100 where wet concrete 102 resides. Using level sensor(s) 22, the operator manipulates frame 12 until it is level, i.e., plane B-B is parallel to grade level A-A. Next, using elevation sensor 24, blade 16 is moved perpendicular to plane B-B (e.g., manually or in a mechanical fashion as indicated by reference numeral 20 until plane B-B coincides with grade level A-A. Then, blade 16 is rotated as indicated by reference numeral 18 so that blade 16 scrapes and/or pushes concrete 102 so that the area thereof under blade 16 is defined by surface 104 that is coincident with grade level A-A. Such rotation of blade 16 can be manual or mechanized. Finally, blade 16 is moved away from concrete 102 as indicated by reference numeral 20 and system 10 is transported to another location.

It will be readily apparent to one of ordinary skill in the art that wet pad strike off system 10 can be constructed in a variety of ways without departing from the scope of the present invention. Designs can range from entirely manual systems to partially/fully mechanized systems. Practically speaking, systems embodying the concepts of the present invention will typically be partially manual and partially mechanized. In this way, repeatable and affordable wet pad strike off operations can be achieved. Accordingly, the exemplary embodiments described herein have both manual and mechanized elements.

Referring now to FIG. 2, an embodiment of a wet pad strike off system is referenced generally by numeral 30. Those elements that are common with system 10 are designated with the same reference numerals and will not be described further. In system 30, blade 16 and a laser receiver 32 are coupled to one another by coupling arrangement 34 so that they move correspondingly in direction 20 while frame 12 remains stationary. Coupling arrangement 34 is typically supported by frame 12. A linear actuator 36 is coupled to/between frame 12 and coupling arrangement 34. Linear actuator 36 is capable of bi-directional movement 38 that generates corresponding movement of blade 16 as indicated by direction arrow 20. In this embodiment, laser receiver 32 is capable of sensing a laser beam 200 indicative of grade level A-A. Such laser receivers and their use/operation are well known in the art. The output of laser receiver 32 is provided to linear actuator 36 to thereby automatically control and position blade 16 so that plane B-B can coincide with grade level A-A.

Another embodiment of the present invention is illustrated in FIG. 3 as is referenced generally by numeral 40. In this embodiment, a linear actuator 42 is provided in line with support 14. Laser receiver 32 and blade 16 are coupled to frame 12 such that frame 12, blade 16 and laser receiver 32 move in correspondence in direction 20 when support/linear actuator 42 moves as indicated by direction arrow 44. Similar to the previous embodiment, movement of linear actuator 42 in direction 44 is automatically controlled by laser receiver 32.

In each of systems 30 and 40, an operator will manually position frame 12 and level same using level sensor(s) 22. The systems will then automatically position blade 16 so that plane B-B coincides with grade level A-A. Rotation 18 of blade 16 can be a manual or mechanized operation. Typically, a motor (not shown) will be provided to rotate blade 16. In this way, the operator can focus on keeping frame 12 level (using sensor(s) 22) as blade 16 rotates. Accordingly, the following two exemplary constructions utilize a motorized drive system to rotate blade 16.

In the following examples, FIGS. 4 and 5 illustrate a possible construction of system 30, and FIGS. 6 and 7 illustrate a possible construction of system 40. Once again, common reference numerals will be used where appropriate. Referring first to FIGS. 4 and 5, two supports 14 are provided on either side of blade 16. The frame in this embodiment is defined by (i) a horizontal cross-member 120 attachable to supports 14 by means of, for example, manually-operated screw clamps 122 so that the height of cross-member 120 relative to base structure 100 can be easily adjusted, and (ii) a vertical shaft housing 124 that can rotationally support a drive shaft 160 (coupled on one end to blade 16) in an orientation that is perpendicular to plane B-B. Cross-member 120 is rigidly coupled to shaft housing 124. Level sensor 22 can be a spirit level mounted on cross-member 120. A handle 126 can be provided on shaft housing 124 to facilitate manipulation of the system while an operator views level sensor 22.

Linear actuator 36 is coupled on one end thereof to shaft housing 124 and on the other end thereof to a bearing housing 162 fixedly attached to drive shaft 160 while allowing for rotation of drive shaft 160 therein. Laser receiver 32 is also attached to bearing housing 162. For example, laser receiver 32 can be mounted on a mast 320 so that laser receiver 32 can be adjusted in height via a clamp 164 provided on bearing housing 162. The output of laser receiver 32 is provided to a controller 322 which can be incorporated with laser receiver 32 that, in turn, is coupled to linear actuator 36. In this way, laser receiver 32/controller 322 govern the operation (i.e., extension or retraction) of linear actuator 36 and, therefore, the positioning of blade 16 relative to grade level A-A.

As disclosed previously, drive shaft 160/blade 16 can be rotated (as indicated by arrow 18) manually or in a mechanized fashion. In the embodiment of FIGS. 4 and 5, a motor 166 is coupled to drive shaft 160 to provide mechanized rotation. Motor 166 can have an on/off switch (“SW”) 168 to allow for on-demand operation of motor 166. Further, motor 166 could be an attached/detachable unit to allow for the re-charging thereof if battery powered. For example, motor 166 might be embodied in a conventional rechargeable hand-held drill that couples to the end of drive shaft 160.

In operation of this embodiment, an operator positions the system and levels same using level sensor 22. Laser receiver 32/controller 322 are then operated to automatically position plane B-B of blade 16 on grade level A-A. The operator then activates motor 166 to rotate blade 16 to thereby create a wet pad of concrete at grade level A-A.

FIGS. 6 and 7 illustrate a possible construction of system 40 (FIG. 3). In this embodiment, two supports 14 are again provided on either side of blade 16 while the system's frame is defined by (i) two parallel cross-members 120A and 120B, and (ii) a shaft housing 124 rotationally supporting drive shaft 160 coupled to blade 16. Cross-members 120A and 120B are rigidly coupled to shaft housing 124. Lower cross-member 120B defines sleeves 120BS at its outboard ends through which supports 14 pass. Upper cross-member 120A defines mounts 120AM at its outboard ends to provide for the mounting of individually controllable linear actuators 42A and 42B thereto. The extensible/retractable arms 43A and 43B of actuators 42A and 42B, respectively, are rigidly coupled to a corresponding one of supports 14.

In this embodiment, a first level sensor 22A is provided on upper cross-member 120A. Sensor 22A is used to provide an indication of lateral tilt so that plane B-B of blade 16 can be positioned laterally parallel to grade level A-A. More specifically, level sensor 22A (e.g., an inclinometer) produces an electronic indication of lateral tilt that is passed to a controller 222 that is coupled to linear actuators 42A and 42B. Thus, once the system is in place on base structure 100, level sensor 22A/controller 222 operate to automatically controls actuators 42A and 42B to laterally level the frame that positions drive shaft 160/blade 16.

Rigidly coupled to the frame (e.g., shaft housing 124 in the illustrated example) is a mounting mast 320 to support the attachment of laser receiver 32, controller 322 and a second level sensor 22B (e.g., a spirit level) used to plumb the system fore and aft. (Note that the functions of controllers 222 and 322 can be embodied in the same controller apparatus.) With the system leveled laterally and fore/aft, laser receiver 32/controller 322 control the simultaneous extension of linear actuators 42A and 42B to automatically position plane B-B of blade 16 on grade level A-A. Then, as in the previous example, motor 166 is operated to rotate blade 16 and create a wet pad.

Blade 16 can be configured in a variety of ways without departing from the scope of the present invention. That is, blade 16 could be a simple straight edge or could be shaped. One such shaped blade is illustrated in FIGS. 8 and 9 where FIG. 8 is a plan view of blade 16 and FIG. 9 is a cross-sectional view thereof. More specifically, blade 16 is S-shaped with its convex portions 16C forming the leading edge thereof as blade 16 rotates in direction 18. Blade 16 can also have a wing 16W coupled to the trailing edge thereof where wing 16W extends angularly away from blade 16 (FIG. 9). Thus, when blade 16 is positioned such that plane B-B is coincident with grade level A-A, wing 16W extends below grade level A-A and into concrete 102. As blade 16 rotates, wing 16W smoothes and closes the surface of concrete 102 in the fashion of a trowel.

The advantages of the present invention are numerous. A wet pad of concrete is quickly and easily formed using a system that will generate repeatable results. The system lends itself to a variety of manual and semi-automatic configurations so that even lower budget construction operations can achieve consistent wet pad formation.

Although the invention has been described relative to a specific embodiment thereof, there are numerous variations and modifications that will be readily apparent to those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described. 

1. A wet pad strike off system, comprising: a frame including at least one support adapted to rest on a base structure on which a quantity of wet concrete is placed; a blade coupled to and suspended from said frame for relative rotation in a plane; first means, coupled to said blade, for sensing elevation of said blade relative to a grade plane; second means, coupled to said frame, for facilitating adjustment of said frame relative to the base structure so that said plane can be positioned parallel to the grade plane; and third means, coupled to at least one of said blade and said frame, for positioning said plane of said blade coincident with the grade plane.
 2. A wet pad strike off system as in claim 1 wherein said at least one support comprises two supports disposed on either side of said blade.
 3. A wet pad strike off system as in claim 1 wherein a leading edge of said blade defines an S-shape in said plane.
 4. A wet pad strike off system as in claim 1 further comprising a wing coupled to a trailing edge of said blade, said wing extending angularly away from said trailing edge and terminating beneath the grade plane when said plane of said blade is coincident with the grade plane.
 5. A wet pad strike off system as in claim 1 wherein said first means comprises a laser receiver.
 6. A wet pad strike off system as in claim 1 wherein said second means comprises at least one level sensing device coupled to said frame.
 7. A wet pad strike off system as in claim 1 further comprising a shaft fixedly coupled to said blade with a longitudinal axis of said shaft being perpendicular to said plane, said shaft being supported by said frame to permit rotation of said shaft about said longitudinal axis resulting in rotation of said blade in said plane.
 8. A wet pad strike off system as in claim 7 further comprising a motor coupled to said shaft for generating said rotation thereof.
 9. A wet pad strike off system as in claim 1 wherein said third means comprises at least one linear actuator.
 10. A wet pad strike off system, comprising: a frame including at least one support adapted to rest on a base structure on which a quantity of wet concrete is placed; a blade coupled to and suspended from said frame for relative rotation in a plane; first means, coupled to said blade, for sensing elevation of said blade relative to a grade plane; second means, coupled to said blade, for generating on-demand rotation of said blade; third means, coupled to said frame, for facilitating adjustment of said frame relative to the base structure so that said plane can be positioned parallel to the grade plane; and fourth means, coupled to at least one of said blade and said frame, for positioning said plane of said blade coincident with the grade plane, wherein subsequent rotation of said blade can strike off a wet pad of concrete coincident with the grade plane.
 11. A wet pad strike off system as in claim 10 wherein said at least one support comprises two supports disposed on either side of said blade.
 12. A wet pad strike off system as in claim 10 wherein a leading edge of said blade defines an S-shape in said plane.
 13. A wet pad strike off system as in claim 10 further comprising a wing coupled to a trailing edge of said blade, said wing extending angularly away from said trailing edge and terminating beneath the grade plane when said plane of said blade is coincident with the grade plane.
 14. A wet pad strike off system as in claim 10 wherein said first means comprises a laser receiver.
 15. A wet pad strike off system as in claim 10 wherein said second means comprises a motor.
 16. A wet pad strike off system as in claim 15 wherein said motor is detachable from said blade.
 17. A wet pad strike off system as in claim 10 wherein said third means comprises at least one level sensing device coupled to said frame.
 18. A wet pad strike off system, comprising: a frame including at least one support adapted to rest on a base structure on which a quantity of wet concrete is placed; a rotatable blade assembly coupled to and suspended from said frame, said rotatable blade assembly including a blade that is rotatable in a plane; an elevation sensor coupled to said blade for sensing elevation of said blade relative to a grade plane; a motor coupled to said rotatable blade assembly for generating on-demand rotation of said blade in said plane; at least one level sensing device coupled to said frame and referenced to said plane of said blade for generating indications of a position of said plane relative to the grade plane wherein said frame can be adjusted in position relative to the base structure so that said plane can be positioned parallel to the grade plane; and at least one linear actuator coupled to at least one of said blade and said frame for positioning said blade such that said plane of said blade is coincident with the grade plane.
 19. A wet pad strike off system as in claim 18 wherein said at least one support comprises two supports disposed on either side of said blade.
 20. A wet pad strike off system as in claim 18 wherein a leading edge of said blade defines an S-shape in said plane.
 21. A wet pad strike off system as in claim 18 further comprising a wing coupled to a trailing edge of said blade, said wing extending angularly away from said trailing edge and terminating beneath the grade plane when said plane of said blade is coincident with the grade plane.
 22. A wet pad strike off system as in claim 18 wherein said elevation sensor comprises a laser receiver.
 23. A wet pad strike off system as in claim 18 wherein said indications generated by said at least one level sensing device are selected from the group consisting of visual and electronic indications.
 24. A wet pad strike off system as in claim 18 wherein said motor is detachable from said rotating blade assembly. 